Let loose your Dark Side (MHA: Izuku Midoriya was a completely powerless boy in a world were just about every single person he knows has superpowers called Quirks. Years of discrimination and mockery had not yet deterred him from his dream yet however, to become a modern-day hero just like his model the number 1 hero and Symbol of Peace All Might.

As if the universe itself had finally heard his prayers, he finally had his chance of becoming a hero after his very idol had seen his heroic spirit when Izuku charged in to save his ex-childhood friend turned bully Katsuki Bakugo and decided that he should inherit his Quirk: One For All.

Izuku would now train and attend the best pro hero academy in Japan: UA. However, after a few faculty shifts a new Principle had come in to office after the previous Principal Nezu was let go. The mysterious but charismatic Principal Shigaraki has now taken a unique interest in the aspiring hero student Izuku.

Little does everyone know that "Principal Shigaraki" is actually the ancient villain All For One the first supervillain that had rose to power at the Dawn of Quirks with his unique Quirk to steal other Quirks. Once assumed dead after his fight with a hero many years ago, he now lives among the very heroes he is at war at. Secretly molding the future generation into the worst versions, they could be while also secretly inciting catastrophes such as gathering villains to attack his own students, sponsoring both Quirk Supremacist and Anti-Quirk terrorist groups to go to war and taking control of what remains of the ancient Yakuza organisations.

With him pulling all the strings his goal to once more rule all of Japan would be soon. He just had to remove one more obstacle, he had to turn the 9th Holder of One For All, his ancient enemy and the successor to his foe All Might, to willingly become his successor instead. To turn this aspiring and sweet summer child into his own protégé of evil and have him rule beside him. Forever removing any threat to his new Empire.

Basically, what if All For One was UA's Principle. Inspired by The Star Wars Prequels.)